biostudies-literatureUnknown3(6)Seki YAMEDJapan Society for the Promotion of Science<h4>Background</h4>The Omicron variant of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) was identified in Japan in November 2021. This variant contains up to 36 mutations in the spike protein, the target of neutralizing antibodies, and can escape vaccine-induced immunity. A booster vaccination campaign began with healthcare workers and high-risk groups. The safety and immunogenicity of the three-dose vaccination against Omicron remain unknown.<h4>Methods</h4>A total of 272 healthcare workers were initially evaluated for long-term vaccine safety and immunogenicity. We further established a vaccinee panel to evaluate the safety and immunogenicity against variants of concern (VOCs), including the Omicron variants, using a live virus microneutralization assay.<h4>Findings</h4>TwMed (New York, N.Y.)406-421.e4https://www.ebi.ac.uk/biostudies/studies/S-EPMC9040508biostudies-literatureSafety and immunogenicity of the Pfizer/BioNTech SARS-CoV-2 mRNA third booster vaccine dose against the BA.1 and BA.2 Omicron variants.PMC9040508Sasaki KSuzuki TFukushi SSeki YMizukami TTakahashi YYato YMoriyama SNojima KNumata NKuzuoka THamaguchi IYoshihara YWagatsuma AMaeda KMomose HfalseSafety and immunogenicity of the Pfizer/BioNTech SARS-CoV-2 mRNA third booster vaccine dose against the BA.1 and BA.2 Omicron variants.<h4>Background</h4>The Omicron variant of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) was identified in Japan in November 2021. This variant contains up to 36 mutations in the spike protein, the target of neutralizing antibodies, and can escape vaccine-induced immunity. A booster vaccination campaign began with healthcare workers and high-risk groups. The safety and immunogenicity of the three-dose vaccination against Omicron remain unknown.<h4>Methods</h4>A total of 272 healthcare workers were initially evaluated for long-term vaccine safety and immunogenicity. We further established a vaccinee panel to evaluate the safety and immunogenicity against variants of concern (VOCs), including the Omicron variants, using a live virus microneutralization assay.<h4>Findings</h4>Tw2022-01-01T00:00:00Z2022 Jun2026-05-09T15:10:55.749Z2025-02-18T23:35:50.243ZS-EPMC90405083581593310.1016/j.medj.2022.04.013